<?php
/**
 * Zend Framework
 * LICENSE
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 * @category Zend
 * @package Zend_Cache
 * @subpackage Zend_Cache_Backend
 * @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license http://framework.zend.com/license/new-bsd New BSD License
 * @version $Id: ZendServer.php 24593 2012-01-05 20:35:02Z matthew $
 */
/**
 *
 * @see Zend_Cache_Backend_Interface
 */
require_once 'Zend/Cache/Backend/Interface.php';
/**
 *
 * @see Zend_Cache_Backend
 */
require_once 'Zend/Cache/Backend.php';

/**
 *
 * @package Zend_Cache
 * @subpackage Zend_Cache_Backend
 * @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license http://framework.zend.com/license/new-bsd New BSD License
 */
abstract class Zend_Cache_Backend_ZendServer extends Zend_Cache_Backend implements Zend_Cache_Backend_Interface {

    /**
     * Available options
     * =====> (string) namespace :
     * Namespace to be used for chaching operations
     * @var array available options
     */
    protected $_options = array('namespace' => 'zendframework');

    /**
     * Store data
     * @param mixed $data Object to store
     * @param string $id Cache id
     * @param int $timeToLive Time to live in seconds
     * @throws Zend_Cache_Exception
     */
    abstract protected function _store ($data, $id, $timeToLive);

    /**
     * Fetch data
     * @param string $id Cache id
     * @throws Zend_Cache_Exception
     */
    abstract protected function _fetch ($id);

    /**
     * Unset data
     * @param string $id Cache id
     */
    abstract protected function _unset ($id);

    /**
     * Clear cache
     */
    abstract protected function _clear ();

    /**
     * Test if a cache is available for the given id and (if yes) return it (false else)
     * @param string $id cache id
     * @param boolean $doNotTestCacheValidity if set to true, the cache validity won't be tested
     * @return string cached datas (or false)
     */
    public function load ($id, $doNotTestCacheValidity = false) {
        $tmp = $this -> _fetch ($id);
        if ($tmp !== null) {
            return $tmp;
        }
        return false;
    }

    /**
     * Test if a cache is available or not (for the given id)
     * @param string $id cache id
     * @return mixed false (a cache is not available) or "last modified" timestamp (int) of the available cache record
     * @throws Zend_Cache_Exception
     */
    public function test ($id) {
        $tmp = $this -> _fetch ('internal-metadatas---' . $id);
        if ($tmp !== false) {
            if ( ! is_array ($tmp) ||  ! isset ($tmp['mtime'])) {
                Zend_Cache::throwException ('Cache metadata for \'' . $id . '\' id is corrupted');
            }
            return $tmp['mtime'];
        }
        return false;
    }

    /**
     * Compute & return the expire time
     * @return int expire time (unix timestamp)
     */
    private function _expireTime ($lifetime) {
        if ($lifetime === null) {
            return 9999999999;
        }
        return time () + $lifetime;
    }

    /**
     * Save some string datas into a cache record
     * Note : $data is always "string" (serialization is done by the
     * core not by the backend)
     * @param string $data datas to cache
     * @param string $id cache id
     * @param array $tags array of strings, the cache record will be tagged by each string entry
     * @param int $specificLifetime if != false, set a specific lifetime for this cache record (null => infinite lifetime)
     * @return boolean true if no problem
     */
    public function save ($data, $id, $tags = array(), $specificLifetime = false) {
        $lifetime = $this -> getLifetime ($specificLifetime);
        $metadatas = array('mtime' => time (), 'expire' => $this -> _expireTime ($lifetime));
        if (count ($tags) > 0) {
            $this -> _log ('Zend_Cache_Backend_ZendServer::save() : tags are unsupported by the ZendServer backends');
        }
        return $this -> _store ($data, $id, $lifetime) && $this -> _store ($metadatas, 'internal-metadatas---' . $id, $lifetime);
    }

    /**
     * Remove a cache record
     * @param string $id cache id
     * @return boolean true if no problem
     */
    public function remove ($id) {
        $result1 = $this -> _unset ($id);
        $result2 = $this -> _unset ('internal-metadatas---' . $id);
        return $result1 && $result2;
    }

    /**
     * Clean some cache records
     * Available modes are :
     * 'all' (default) => remove all cache entries ($tags is not used)
     * 'old' => unsupported
     * 'matchingTag' => unsupported
     * 'notMatchingTag' => unsupported
     * 'matchingAnyTag' => unsupported
     * @param string $mode clean mode
     * @param array $tags array of tags
     * @throws Zend_Cache_Exception
     * @return boolean true if no problem
     */
    public function clean ($mode = Zend_Cache::CLEANING_MODE_ALL, $tags = array()) {
        switch ($mode) {
            case Zend_Cache::CLEANING_MODE_ALL :
                $this -> _clear ();
                return true;
                break;
            case Zend_Cache::CLEANING_MODE_OLD :
                $this -> _log ("Zend_Cache_Backend_ZendServer::clean() : CLEANING_MODE_OLD is unsupported by the Zend Server backends.");
                break;
            case Zend_Cache::CLEANING_MODE_MATCHING_TAG :
            case Zend_Cache::CLEANING_MODE_NOT_MATCHING_TAG :
            case Zend_Cache::CLEANING_MODE_MATCHING_ANY_TAG :
                $this -> _clear ();
                $this -> _log ('Zend_Cache_Backend_ZendServer::clean() : tags are unsupported by the Zend Server backends.');
                break;
            default :
                Zend_Cache::throwException ('Invalid mode for clean() method');
                break;
        }
    }

}
